The Mets are cautiously optimistic Yoenis Cespedes’ left hamstring will allow him back into the starting lineup Tuesday.

Cespedes on Sunday took indoor batting practice — his most significant step since injuring the hamstring three days earlier — and was available for pinch-hitting duty in the Mets’ 6-3 loss to the Nationals at Citi Field.

Cespedes, who would have batted if the Mets got another runner on base in the ninth inning following Jay Bruce’s leadoff single, later told manager Terry Collins he expects to be ready for Tuesday’s game against the Braves.

But Collins also wants to ensure Cespedes doesn’t rush back to the lineup and aggravate the hamstring. Collins compared the situation to last August, when Cespedes took two games off to rest his sore quadriceps and then returned to the lineup and aggravated the injury, necessitating a disabled list stint.

Collins conceded the DL could be an option if Cespedes isn’t ready for Tuesday. In such a scenario, the Mets could backdate a stay on the 10-day disabled list to April 21.

Travis d’Arnaud’s bruised right hand is still preventing him from finishing his throws. Collins had d’Arnaud listed in the lineup Sunday, but then changed course and selected Kevin Plawecki behind the plate.

“[D’Arnaud] is very concerned if he goes and plays that this gets worse,” Collins said. “We have no medical evidence that says it will, but we have none that says it won’t. He went out and threw and said it really hurts to throw. And I’m not going to put the poor guy in a situation where he’s going to get embarrassed if he can’t throw the ball to second at all. I don’t want it to be a track meet.”